/Engine/Plugins/Experimental/PCG/Source/PCG/Public/PCGSubgraph.h
There is a weird issue where the BP class is not set correctly in some Server cases. We can try to recover if the PropertyClass is null.
virtual void FixingOverridableParamPropertyClass ( [FPCGSettingsOverridableParam](API\Plugins\PCG\FPCGSettingsOverridableParam) & Param ) const